Related papers: Heavy element enrichment in the IGM at high redshi…

We present a direct measurement of the metallicity distribution function for the high redshift intergalactic medium. We determine the shape of this function using survival statistics, which account for both detections and non-detections of…

Using the Cosmic Origins Spectrograph aboard the Hubble Space Telescope, we measured the abundances of six ions (C III, C IV, Si III, Si IV, N V, O VI) in the low-redshift (z < 0.4) intergalactic medium and explored C and Si ionization…

We present the results of the largest survey to date for intergalactic metals at redshifts z > 5, using near-IR spectra of nine QSOs with emission redshifts z(em) > 5.7. We find, for the first time, a change in the comoving mass density of…

New measurements of the z~6 intergalactic CIV abundance are presented, using moderate resolution IR spectra of two QSOs taken with GNIRS on Gemini South. These data were systematically searched for high redshift CIV absorption lines, using…

We study the clustering properties of metals in the intergalactic medium (IGM) as traced by 619 CIV, 81 SiIV, N >= 10^12 cm^-2 and 316 MgII, and 82 FeII N >= 10^11.5 cm^-2 absorption components in 19 high signal-to-noise (60-100 per pixel),…

We have studied the abundance of oxygen in the IGM by analyzing OVI, CIV, SiIV, and HI pixel optical depths derived from a set of high-quality VLT and Keck spectra of 17 QSOs at 2.1 < z < 3.6. Comparing OVI and CIV optical depth ratios to…

We measure the spatial clustering of metals in the intergalactic medium from z = 1.7 to 3.0, as traced by 643 CIV and 104 SiIV N >= 10^12 cm^-2 absorption systems in 19 high signal-to-noise (40-80) and high resolution (R = 45000) quasar…

In this work, we investigate the abundance and distribution of metals in the intergalactic medium (IGM) at $\langle z \rangle \simeq 2.8$ through the analysis of an ultra-high signal-to-noise ratio UVES spectrum of the quasar HE0940-1050.…

The abundances of metals in the intergalactic medium (IGM) can be used to constrain the amount of star formation at high redshift and the spectral shape of the ionizing background radiation. For both purposes it is essential to measure the…

Observations of quasar absorption line systems reveal that the z=3 intergalactic medium (IGM) is polluted by heavy elements down to HI optical depths tau_HI<<10. What is not yet clear, however, is what fraction of the volume needs to be…

We conduct an ultraviolet (HST and FUSE) spectroscopic survey of HI (Lyman lines) and seven metal ions (OVI, NV, CIV, CIII, SiIV, SiIII, FeIII) in the low-redshift intergalactic medium (IGM) at z<0.4. We analyzed 650 Lya absorbers over…

We have examined the metal enrichment of the intergalactic medium (IGM) based on a galactic wind model. A galactic wind driven by supernovae brings metallic gas to the IGM but not so far beyond the gravitational potential. The expanding…

A search for O VI at redshifts corresponding to Ly-alpha lines in the z_em ~ 2.4 QSOs HE1122-1648 and HE2217-2818 reveals that a substantial fraction of those with H I column densities log N(HI) > 14 (cm^{-2}) are highly ionized and show…

This paper presents ionization-corrected measurements of the carbon abundance in intergalactic gas at 4.0 < z < 4.5, using spectra of three bright quasars obtained with the MIKE spectrograph on Magellan. By measuring the CIV strength in a…

The Intergalactic Medium (IGM) contains $>$50% of the baryonic mass of the Universe, yet the mechanisms responsible for keeping the IGM ionized has not been fully explained. Hence, we investigate ion abundances from the largest blind QSO…

Column density distribution functions of CIV with 12.05 < log (N) < 14.35 and SiIV with 11.70 < log (N) < 13.93 have been obtained using 81 CIV absorbers and 35 SiIV absorbers redward of the Ly alpha forest in the lines of sight to seven…

We use high spectral resolution (R=45000) and high signal-to-noise ratio (S/N \~ 35-70 per pixel) spectra of 19 high-redshift (2.1<z_em<3.2) quasars to investigate the metal content of the low-density intergalactic medium using…

We present the results of observations taken with the X-shooter spectrograph devoted to the study of quasars at z ~ 6. This paper focuses on the properties of metals at high redshift traced, in particular, by the C IV doublet absorption…

We use high-quality, medium-resolution {\it Hubble Space Telescope}/Cosmic Origins Spectrograph (\HST/COS) observations of 82 UV-bright AGN at redshifts $z_{AGN}<0.85$ to construct the largest survey of the low-redshift intergalactic medium…

We present the results from our search for C IV in the intergalactic medium at redshifts z=5.3-6.0. We have observed four z~6 QSOs with Keck/NIRSPEC in echelle mode. The data are the most sensitive yet taken to search for C IV at these…